This article will not cover basic features of neither Perl nor Oracle.
It will also not cover the installation of Perl, Oracle, DBI or DBD:: Oracle. This is simply an introduction to using Oracle with Perl DBI.
DBI is a Perl module, well documented in both online sources and the "Programming the Perl DBI" book by Alligator Descartes, Alistair Carty, Tim Bunce and Linda Mui (O'Reilly, ISBN:1565926994) but still, I can see questions about using DBI with Oracle on Oracle USENET groups. Oracle has many features and data types, while using DBI with each particular feature is not always entirely trivial.
The purpose of this article is to cover many of those uses from Perl practitioner's point of view.
I've been dealing with this error off and on for the last 3 years and I just wanted to verify that my understanding of its cause is accurate.
Cause 1) There is only one user logged into the database.
Are there any other scenarios where ORA-01555 can occurr?
Because a cursor is an actual object inside the database engine, there is a little overhead involved in creating the cursor and destroying it.
Also, a majority of cursor operations occur in tempdb, so a heavily used tempdb will be even more overloaded with the use of cursors.
This article was created on Red Hat Fedora Core 4, with Oracle 10.2.0.2 and Perl 5.8.6.
The decision not to cover the installation was made because the installation is different for each operating system, while I'd like to concentrate on the common features, the features that can be used across the whole range of supported systems.You'll never have a good hit ratio if everyone submits "unique" sql.